Linear alpha-olefins (LAOS) find application in a wide variety of end uses including intermediates in the production of polyalphaolefins (PAOs), fine chemicals, epoxides, amines, oxo alcohols, synthetic lubricants, synthetic fatty acids, alkylated aromatics, synthetic lubricants, surfactant intermediates, base oil for synthetic drilling fluids, and as lubricant additives. LAOs of industrial interest include 1-butene, 1-hexene, and 1-octene to 1-tetradecene, with 1-decene being a commonly used material.
The two main commercial routes to LAOs are the oligomerization of ethylene and the Fischer-Tropsch process which converts carbon monoxide and hydrogen into liquid hydrocarbons. The major source of the starting materials for these commercial routes to LAOs are nonrenewable feedstreams including petroleum, coal, and natural gas. Recently there has been a strong incentive to produce fuels and chemical products from renewable feedstreams such as natural oils. For example, the development of biodiesel fuels is of great interest and some biodiesel-based materials are already commercially produced. Specifically, bio-diesel fuels made from plant oils are already on the market and demand for such fuels is expected to increase significantly over the next decade. To support this increased demand, a large amount of natural oils and ethanol is expected to become available.
LAOs may be produced from such renewable feedstreams by a cross-metathesis reaction of the renewable feedstream with an olefin, such as ethylene, in the presence of a metathesis catalyst. For example, U.S. Pat. No. 4,545,941, discloses production of certain alpha-olefins by reacting triglycerides having fatty acid esters containing isolated carbon-carbon double bonds with ethylene at an ethylene partial pressure of 200-550 psig in the presence of a metathesis catalyst, specifically a catalyst comprising a tungsten compound and a tin compound (e.g., tungsten hexachloride and tetramethyl tin (WCl6/(CH3)4Sn)).
Also, Ahmad et al., Co-Metathesis Reaction of Crude Palm Oil and Ethene, Journal of the American Oil Chemists′ Society Pub. No. 72(6), 757-758 (1995), discloses the co-metathesis reaction of crude palm oil with ethene in the presence of tungsten hexachloride and tetramethyl tin (WCl6/(CH3)4Sn), followed by termination of this reaction with methanol, which gives terminal olefins. The major metathesis products are 1-decene and methyl-9-decenoate.
Further, U.S. Patent Publication No. 2007/0179307 discloses a process for co-producing an olefinic fraction and a composition of diacids or diesters of fats from an unsaturated fat and ethylene. The process comprises, in succession: a) metathesis of an unsaturated fat with ethylene in the presence of a metathesis catalyst and at least one non-aqueous ionic liquid; b) separating and recycling the ionic liquid used in the first step; c) separating, by distillation, the olefinic fraction (fraction A) from the unsaturated fat mono-ester or mono-basic acid fraction (fraction B) formed in step a); d) homometathesis of the mono-unsaturated fat ester or acid cut (fraction B), which allows the co-production of unsaturated fat diesters or diacids (fraction C) and ethylene which is recycled to the first metathesis step of the process; and e) optionally, recycling the ionic liquid containing the catalyst used in step d). Particularly preferred starting material is an oleic sunflower seed oil, an oleic rapeseed oil, or a mixture of mono-alcohol esters of said oils, whereupon the process can produce both an olefinic fraction (mainly composed of 1-decene) and a composition of diesters or diacids; where, in general, over half of the chains constitute unsaturated C18 chains (mainly composed of 9-octadecene-1,18-diacid or diester).
LAOS, regardless of source, may be polymerized to produce PAOs. PAOs generally refer to a class of hydrocarbons manufactured by the catalytic oligomerization (polymerization to generally low-molecular-weight products) of LAO monomers. Co-oligomers of lower olefins, such as, ethylene and propylene, may also be used to produce PAOs, including the ethylene-alphaolefin copolymers described in U.S. Pat. No. 4,956,122 and the patents referred to therein.
Specifically, PAOs of different viscosity grades may be produced by the polymerization of LAO feeds in the presence of a catalyst, usually AlCl3, BF3, promoted AlCl3, or promoted BF3. These catalysts exhibit higher reactivity toward LAOs than towards branched or internal olefins. Therefore, when oligomerizing a crude feed containing LAOS, branched olefins, and/or internal olefins with these catalysts, a process-generated side stream of unreacted monomers (branched olefins and/or internal olefins) is usually produced.
Processes for the production of PAOs are disclosed, for example, in the following patents: U.S. Pat. Nos. 3,149,178; 3,382,291; 3,742,082; 3,780,128; 3,833,678; 3,997,621; 4,172,855; 4,956,122; 6,410,812; 6,949,688; WO 2007/011,462; and WO 2007/111,776, all of which are incorporated by reference.
Other publications propose polymerization of various alpha-olefins in the presence of metallocene catalyst systems to provide polymers having various utilities, such as lubricant components. For example, WO 2007/011462 discusses a process for producing PAOs of high viscosity index (HVI-PAOs), including contacting a feed comprising a mixture of LAOs with an activated metallocene catalyst to produce liquid polymers for use in lubricant components or as functional fluids. The copolymer composition may be made from at least two different alpha-olefins of C3 to C30 range, with monomers randomly distributed in the polymers. In an embodiment, one of the monomers is a higher alpha-olefin, such as one chosen from C12 to C18 alpha-olefins, and the second one or more alpha-olefin is, e.g., chosen from C3 to C7 alpha-olefins. In another embodiment, propylene or 1-butene, which are readily available from refinery or petrochemical plants, are used as one of the feed components. The resulting copolymers are said to have useful lubricant properties, including excellent viscosity index, pour point, and low temperature viscometrics, by themselves or as a blend fluid with other lubricants or polymers.
In another example, U.S. Pat. No. 5,859,159 is directed towards a dilute process for the polymerization of non-ethylene, alpha-olefin homopolymers, and copolymers in the presence of metallocene catalyst systems. The alpha-olefin feed stream used in the process comprises at least one alpha-olefin, such as propylene, 1-butene, 1-pentene, 4-methyl-pent-1-ene, 1-hexene, 1-octene, and higher alpha-olefins up to and including 1-nonadecene, e.g., mixtures of propylene and 1-butene. The 1-butene-propylene polymers of most of the examples have an isotactic index of at least 80%. Other examples include U.S. Pat. No. 6,706,828, which discusses production of PAOs in the presence of meso-forms of certain metallocene catalysts under high hydrogen pressure with methyl alumoxane as an activator. WO 02/14384 and WO 99/67347 discuss similar topics. Other examples include U.S. Pat. Nos. 4,704,491; 5,087,788; 5,688,887; 6,043,401; 6,133,209; 6,414,090; 6,414,091; 6,548,724; 6,706,828; 6,713,438; WO 96/23751; WO 03/020856; and EP 0 613 873.
Furthermore, WO 2010/074738 discloses an integrated production of synthetic PAOs from renewable feedstreams by metathesis of the renewable feedstream with an alpha-olefin then polymerization of the resulting LAOs with a polymerization catalyst, such as AlCl3, BF3, or a metallocene catalyst promoted with an alumoxane or a non-coordinating anion. When Ziegler catalysts, CrO/SiO2 catalysts, or metallocene catalysts are used for the polymerization process, only LAOs will be incorporated to give polyalphaolefins (PAOs). The internal olefins will not be incorporated into the polymer (WO 2010/074738, paragraph [0045]).
There remains a need for efficient methods of incorporating LAOs into PAOs to provide new PAOs with desirable properties. There remains a need to effectively incorporate internal olefins (especially alpha, internally unsaturated, non-conjugated olefins or “AIUNOs”) into PAOs to produce new LAO-AIUNO copolymers. There is also a need for methods of producing LAO-AIUNO copolymers from feedstreams containing LAOs and AIUNOs, in particular, from renewable feedstreams. There is further a need for commercially economical routes to desirable PAOs, in particular, PAO which can be functionalized, and in turn used for the preparation of functionalized PAOs, such as LAO-AIUNO copolymers.